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THE OHIO STATE UNIVERSITY BULLETIN 
Vol. XXII September, 1917 No. 4 


The Chemical Examination 
of Natural Brines 

BY 

ORLAND R. SWEENEY 

AND ) 

JAMES R. WITHROW 



BULLETIN No. 17 
COLLEGE OF ENGINEERING 

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PUBLISHED BY THE UNIVERSITY 
COLUMBUS, OHIO 


Entered as Second Class Matter, November 17, 1905, at the Post Office at Columbus, Ohio, 

under Act of Congress, July 16, 1894. 












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[Reprinted from the Journal of Industrial and Engineering Chemistry, 
Vol. 9, No. 7. page 671. July, 1917.] 


THE CHEMICAL EXAMINATION OF NATURAL BRINES' 

By O. R. Sweeney and James R. Withrow 

The proper analysis of natural brines has always 
been important. They are used by chenTcal manufac¬ 
turers to make comparisons with a view to reaching 
decisions as to prospective yields of salt, bromine and 
other products. The war-time elevation of the price 
of bromine from 30 cents to as high as $6.50 per lb., 
as well as a similar elevation of other products derived 
from natural brine, has given rise to search for addi¬ 
tional sources of these products and a carefitl scrutiny 
of many of the brines encountered in oil, gas and coal 
development, and hitherto wasted. As a result many 
analyses have been made in the last three years as a 
basis for manufacturing consideration. Some of these 
were made in the laboratories of manufacturers them¬ 
selves and some by consulting chemists. Analyses 
from both sources have come into the hands of the 
authors as the basis for report upon prospective 
manufacturing values. We, also, have had occasion 
to make check or confirmatory analyses. 

It early became evident that there was no standard 
or uniform procedure being followed by the different 
workers. To this fact may be due a large part of the 
non-agreement encountered from time to time, though 
inexperience with this type of analysis is also a factor. 
Few chemists, even water analysts, are experienced in 
such a type of work as bromine determination in brine. 
This may be shown best by citing a report to its 
president by the laboratory of the chemical company. 
The letter from the president of one chemical company 
to another stated: 

“The analysis of the two samples of brine which you 
sent us has been completed and it was some job. The 
results are as follows: 


Depth. 

Diameter. 

Specific Gravity of Brine. 

CaO. 

Br. 

Halides (as sodium halide) 
Iodine. 


Well A 

1200 ft. 

8 in. 

1.071 

0.69 per cent 
0.42 
9.21 
None 


Well B 

1200 ft. 

4 in. 

1.070 

0.68 per cent 
0.22 
9.26 
None” 


These samples were from a brine whose composition 
was well known to us. Furthermore, they were on 

1 Read before the Industrial Division, Kansas City Meeting of the 
American Chemical Society, April 12. 1917. 

(0 









the same property. It will be noticed that they are 
of the same depth and also the same specific gravity, 
CaO content, and halide content. Nevertheless, they 
are reported of different bromine content—adivergence 
of nearly ioo per cent. Such a divergence would 
be a very important matter industrially, for one of 
these wells would give nearly twice-the yield of bromine 
for the same turnover of salt and calcium chloride 
and at the same fuel cost as the other well. Consid¬ 
ering the difficulty of bromine determination, by the 
usual methods, the infrequency of demand for it and 
the concordance of all other determinations on these 
two brines one is tempted to suspect the accuracy of 
the bromine determinations. As a matter of fact even 
the lower value is over twice the bromine content of 
the field in question as shown by both analyses by 
various chemists and experience of all the plants opera¬ 
ting on this particular brine. 

Such situations give rise to controversy and dis¬ 
credit analytical chemistry. An examination of the 
literature for a basis for standard or uniform procedure 
disclosed no exact one which could be recommended. 
The procedures described for the examination of 
“mineral water” are not applicable directly. Certain 
modifications which our experience has introduced 
are recorded here. Not all of the procedures de¬ 
scribed have been exhaustively studied as yet. The 
purpose of this paper is to make a beginning with 
the hope that others, who have had experience in 
this work, will contribute their experiences, or will 
criticize these procedures. In this way a procedure 
may be developed which may be accepted as standard. 
The object is to develop a method which will meet 
the needs of the manufacturing chemist rather than a 
method of exhaustive analysis. Brevity and speed 
of manipulation, with reasonable accuracy, are, there¬ 
fore, the requirements. 

ANALYTICAL PROCEDURES 

sample —The sample when pumped from the earth 
will generally be clear, but on standing it becomes 
turbid due to the separation of a brown precipitate. 
This precipitate is mainly iron, but may contain silica 
and alumina. It is probably caused by oxidation 
and hydrolysis of ferrous bicarbonate. Generally 
by the time the sample will have reached the chemist 
the iron will have separated. The scheme of agita¬ 
tion to suspend the deposit uniformly through the 

(2) 


.liquid before taking a part for analysis is inaccurate, 
as experiments have shown. Furthermore, the specific 
gravity is changed and this will affect the entire 
percentage composition. Consideration of this point 
has led us to conclude that the best procedure w'ould 
be to collect a sample of about one liter, allow it to 
oxidize and settle completely, determine the amount 
of deposit, and then make analyses on the filtered 
sample. The analysis would not be exactly that of 
the original brine, but the difference will be very 
slight, and, since this procedure gives more nearly 
the thing that the manufacturer wants, it is best to 
proceed in this manner. 

deposit on standing (aeration) —The sample of 
about one liter, which will usually contain some de¬ 
posit, is allowed to stand, with occasional shaking, 
and removing of the stopper, for two or three days, 
or until deposition is complete and the precipitate set¬ 
tles well. The height of the liquid is carefully marked 
on the outside of the bottle, and the entire sample 
is then filtered, rejecting the first ioo cc. The precipi¬ 
tate is well washed, ashed and ignited to constant 
weight. The bottle is dried and the amount of water 
which it contained to the mark is determined. With 
these data the grams per liter are calculated, using the 
specific gravity of the filtered sample, and the result 
recorded as “Deposit on Aeration .” The errors will 
not be large if percentages be calculated, using this 
figure. Since in the industries all natural brines are 
exposed to air and allowed to settle before they are 
further treated, this value is just what is wanted by 
the manufacturer. Further examination of the pre¬ 
cipitate is not necessary. It is a question whether 
or not it would be fair to assume the precipitate to 
be iron oxide (Fe 2 0 3 ) and calculate it to, and report 
it as, ferrous bicarbonate. 

specific gravity —The specific gravity is obtained 
by the Westphal balance, and is taken at 15 0 C., 
although perhaps it would be better to use 20 0 C., 
since this is more nearly the average temperature. 
The specific gravity of the fresh brine will be different 
from that of the sample through which the precipitate 
is suspended, and this in turn will be different from 
the filtered Sample. On one brine, for example, 
the specific gravity of the filtered sample was 1. 2307, 
while that of the sample in which the precipitate was 
suspended was 1.2342. If the chemist could take 
the specific gravity of the clear brine as soon as pumped 

(3) 


from the well it would no doubt be best, from the 
point of view of the original brine but this will gen¬ 
erally be impractical. Even if the specific gravity 
could be obtained on the fresh brine there would be 
some volume change after the precipitate settled and 
a small error would be introduced when taking a fil¬ 
tered sample for later analyses. For these reasons, 
and also because the manufacturer is interested in 
the settled brine, it is believed that the best procedure 
is to use the filtered, aerated brine, and to determine 
the specific gravity with a Westphal balance at 15 0 C(?). 
This value is used in calculating percentages. 

total solids —Many chemists omit this determina¬ 
tion because of its questionable accuracy, but its value 
in calculating total water content for “evaporation fuel” 
comparisons makes it important. Brines rich in CaCh 
require a rather high temperature, above 160° C., to 
expel the water completely. At this temperature 
the magnesium and calcium salts lose a part of their 
acid constituents, and a wide range of values will be 
obtained, depending on the temperature and dura¬ 
tion of heating. The total solids can be calculated 
from the complete analysis, but this value should be 
checked by the total solids as obtained by evapora¬ 
tion. This point is being studied in this laboratory 
at the present time, and it is hoped that by a suitable 
arrangement the volatilized acids may be collected, 
titrated and then be added to the residual weight of the 
total solids. It may be that a weighed excess of some 
base may be added to retain the acid which is other¬ 
wise volatilized. The constituents likely to volatilize 
are chlorine, bromine, iodine (slight), sulfur trioxide 
and carbon dioxide (slight). The total solids are de¬ 
termined in the filtered sample, using 25-cc. portions 
and should be reported as Total Solids by Evaporation. 
This gives the manufacturer a basis for a reasonable 
estimation of the water to be evaporated in working 
the brine. 

silica —A 25-cc. portion of the filtered brine is 
acidulated with 5 cc. of concentrated hydrochloric 
acid and is evaporated to dryness. It is then dried 

at 120 0 C., or higher if necessary, for an hour. Five 

« 

cc. of hydrochloric acid are then added, the vessel is 
warmed, 20 cc. of water are added, and, after warming, 
the whole is filtered and washed free from chlorides. 
The filtrate is evaporated and treated as just de¬ 
scribed, and the operation is repeated on the second 
filtrate. The combined precipitates are ignited in a 

(4) 


platinum crucible, and weighed. The residue is 
treated with sulfuric and hydrofluoric acids. The 
loss in weight is reported as silica , and the residue is 
added to the iron and alumina. 

iron and aluminum —The filtrate and washing, 
w T hich should contain 5 cc. of concentrated hydrochloric 
acid, are treated with a few drops of nitric acid, boiled 
a few minutes, and then made alkaline with ammonia. 
It is then boiled until all the ammonia is expelled, and 
after standing, is filtered, washed and ignited in the 
crucible from which the silica was expelled. The 
residue is reported as Iron and Aluminum Oxides. A 
separation of the iron and aluminum is not necessary. 
The results should be reported separately from the 
iron which separated on aeration. It should be remem¬ 
bered that the iron, aluminum and silica are not in 
solution as oxides, but as salts. For this reason there 
will be a slight difference between the total solids on 
evaporation and the calculated total solids. 

Much time is saved if the iron, alumina and silica 
are all precipitated together, with ammonia. The 
amount of silica remaining in solution is very small. 
These constituents have no commercial value, and 
need not be reported separately. It should be remem¬ 
bered in this latter case that ammonium chloride must 
be added. 

calcium —The filtrate from the iron and aluminum 
is diluted to 250 cc. and 25 cc. are taken; this is diluted 
to 150 cc., heated to boiling and a hot 10 per cent 
solution of ammonium oxalate is added in excess. 
After standing for some time (15 minutes), it is fil¬ 
tered and washed with hot water. The precipitate 
is dissolved in warm dilute hydrochloric acid, a little 
ammonium oxalate solution added, and ammonia 
then slowly added to complete the precipitation. 
The precipitate is filtered out, after standing one-half 
hour, and is ignited to the oxide and weighed, or is 
dissolved in dilute sulfuric acid and titrated with 
permanganate. Our experience seemed to show that 
it was not necessary to allow the precipitate to stand 
12 hours as is recommended in some of the books on 
water analysis. The calcium should be reported as 
sulfate and chloride. 

magnesium —The combined filtrates and washings 
from the calcium are acidified with hydrochloric acid, 
a large excess of sodium hydrogen phosphate is added, 
and then ammonium hydroxide with constant stirring 

(5) 


until the liquid smells of ammonia. Ten cc. of strong 
ammonia are added in excess and the whole is allowed 
to stand 12 hours. The precipitate is filtered out, 
washed with dilute ammonia and redissolved in 
hydrochloric acid (1 : 5). The volume is made up to 
75 cc., a little sodium hydrogen phosphate added, 
and then ammonia, drop by drop, with constant 
stirring until the solution smells strongly. After 4 
hours the magnesium is filtered out on an alundum or 
Gooch crucible, washed with 2 per cent ammonia water, 
dried and ignited to Mg9P:>07. If an alundum cruci¬ 
ble is used it should be heated within a glazed cruci¬ 
ble. The magnesium should be calculated to the bro¬ 
mide and chloride. 

The above procedure gave very good results. In 
the usual procedure the filtrate from calcium is evap¬ 
orated to dryness, and the ammonium salts are vola¬ 
tilized. This requires great care, and much time, 
and did not give any better results than the procedure 
described. The reprecipitation must be carried out, 
even on very small amounts. There seems to be 
good authority, however, for the evaporation and 
ignition which we have omitted, and the point should 
be investigated further. 1 

barium and strontium —If no sulfates are present, 
barium and strontium must be looked for. Indeed a 
case is on record where barium, lead and sulfuric acid 
were present simultaneously in a natural mineral 
water. 2 From work in progress in this laboratory it 
seems, however, that in the case of brines, where 
very little C 0 2 is present, that sulfates preclude the 
presence of barium or strontium. Barium oxalate is 
sparingly soluble, and a strontium oxalate is insoluble 
in water. When these metals are present they will 
be partially precipitated along with the calcium. 
This point seems to have been overlooked hitherto. 
In cases where the barium and strontium amount to 
o. 2 per cent the error introduced cannot be neglected. 
The magnesium results may also be affected. It may 
be possible to precipitate the barium and strontium with 
ammonium sulfate before precipitating the calcium, 
but no work has been done on this phase. The fact 
that the barium is not completely precipitated by 

1 In the discussion of this paper in the Industrial Division it was sug¬ 
gested that the speedier method for magnesium, used in Row’s “Technical 
Methods of Ore Analysis,’’ p. 159, might be of service here but we have not 
yet investigated this method, or the method of precipitation with sodium 
hydroxide sometimes used on traces of magnesium. 

2 Carles, Ann. chim. anal., 1902 , 91. 

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ammonium oxalate makes it impossible to apply a 
correction to the calcium precipitate. The determina¬ 
tion of the barium and strontium in the calcium 
precipitate is too time-consuming to be practical for 
the ordinary technical analysis. When the barium 
and strontium content is small the error can be ignored. 
The procedure used was identical with the one de¬ 
scribed in the Department of Agriculturel Bull ., 91, 
“Mineral Waters of the United States,” by J. K. Hay¬ 
wood and B. H. Smith; a simpler method has not yet 
been found. 

ammonia —Traces of ammonia have been reported 
in some brines, but the amount is generally so small 
as to be of no commercial importance. It may be, 
however, that its significance is greater than we 
now know, especially in brines for electrolysis. The 
suggestion has been made by cell operators that nitro¬ 
gen chloride may be connected with the explosions 
which occur from time to time in electrolytic chlorine 
apparatus. If this should prove true the determina¬ 
tion of ammonia will be important. 

SULFURIC ACID, SODIUM AND POTASSIUM -Fifty CC. 

of the filtrate from the iron and alumina are diluted 
to 100 cc. and treated, while boiling hot, with 10 
per cent BaCl 2 solution, adding it slowly, and with 
constant stirring. The BaS 0 4 is filtered off, the paper 
burned off in a porcelain crucible, and the precipitate 
dissolved in a few cc. of warm, concentrated sulfuric 
acid. The solution is now carefully poured into 250 
cc. of water, and, after standing some time, is filtered, 
washed and ignited. It should be reported as calcium 
sulfate. This method of freeing the BaS 0 4 from iron 
and other absorbed matter is very effective. It is 
essentially that taught for decades at the John Harri¬ 
son Laboratory, University of Pennsylvania, Phila¬ 
delphia. 

The filtrate from the sulfuric acid is used for sodium 
and potassium. From this point, the procedure we 
have been using is the same as described in “Mineral 
Waters in the United States,” Department of Agri¬ 
culture Bull ., 91, Loc. cit. It is difficult, however, to de¬ 
termine small amounts of potassium in the presence 
of large amounts of sodium chloride, and it is believed 
that some procedure 1 should be used which will pre¬ 
cipitate most of the sodium first. 

chlorine —The brine should be tested with phenol- 

1 Professor C. W. Foulk. of the Division of Analytical Chemistry o f 
the Ohio State University laboratory, is now investigating this matter. 

( 7 ) 


phthalein. It will usually be neutral, but if it is not, 
it should be made so with NaHSCb solution, io cc. 
of the filtered sample are diluted to a liter and io 
cc. used for titration. This is diluted to 200 cc., 2 cc. of 
K 2 Cr04 solution are added and the mixture is titrated 
to the end-point. Na 2 Cr04 would probably be a 
satisfactory indicator here but we have not yet proved 
this to be true. Take an amount of standard sodium 
chloride solution equivalent to the amount of silver 
nitrate used, dilute to 200 cc. and titrate as before. 
The difference represents the amount necessary to 
affect the indicator and should be subtracted. This 
procedure is accurate enough since the chlorine is 
used only as a check on the analytical work. The 
bromine value must be deducted. 

bromine —The colorimetric procedure, as given for 
ordinary waters, is not usable with brines. Experi¬ 
ments showed that after repeated extraction with 
90 per cent alcohol the residue still contained bromine. 
The distillation methods are time-consuming and not 
very easily manipulated. For these reasons a colori¬ 
metric method was developed. 

Procedure —100 cc. of the brine are made alkaline 
with Na 2 C 0 3 and are evaporated to dryness. It is 
then taken up in water and filtered into a 250-cc. flask. 
It is made distinctly acid with H 2 S 0 4 and is diluted 
to the mark: 25 cc. are pipetted into a 50-cc. Nessler 
tube and chlorine is added until the maximum color 
has developed: 10 cc. of carbon tetrachloride are 
then added, and the mixture is shaken and compared 
with a set of standards made up from NaBr solution 
in the same way. By this rough check the approx¬ 
imate amount of bromine will be discovered, and a 
set of standard solutions are then prepared which are 
very close above and below the unknown solution. 
Again 25 cc. are taken, chlorine water is added to a 
maximum color and the same amount is added to the 
standards; the sample is then shaken with 10 cc. of 
CCI 4 and poured into a wet filter; when the water has 
drained off the filter should be punctured and the liquid 
caught in a 25-cc. Nessler tube (this is best done 
in a darkened room but darkness is not essential).’ 
If a sample does not exactly match the standard the 
colors can be compared by diluting with CC1 4 ; or 
since the operation is so simple, a new set of standards 
can be made up, and then a new determination made. 
If a test shows that all bromine was not extracted by 

( 8 ) 


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io cc. of CC 1 4 a second extraction should be made. 
This is generally not necessary. 

Traces of iodine which are present in most brines 
will not interfere. The iodine need not be reported. 

It is difficult to appreciate the unreliability of pub¬ 
lished statements regarding the occurrence of bromine. 
For instance, although the State of Michigan reports, 
and the most reliable information states, that Midland, 
Mich., brine contains o. 1 per cent of bromine, yet the 
most exhaustive German work on bromine 1 states 
on page 3 that the brine from Midland, Ohio, sic., 
contains 4.18 per cent magnesium bromide which is 
equivalent to 3.63 per cent bromine, or 36 times 
stronger than those who operate on it claim it to be. 

REPORTING RESULTS 

The results should be reported in such a manner 
as to give the manufacturer the thing which he wants. 
The reporting of the constituents as ions, while strictly 
scientific, is of no value to the manufacturer. All 
of the sodium and potassium should be calculated 
to chloride. Since the CaS 0 4 separates on the copper 
tubes in the evaporators the H0SO4 should be reported 
as calcium sulfate. The bromine should be calculated 
as magnesium bromide, since it has long been so con¬ 
sidered in the trade; but bromine as free bromine 
should also be reported. The residual calcium and 
all the magnesium are calculated to chlorides since 
they go on the market as such. Strontium and barium 
should be given as chlorides. The silicon should be 
reported as the oxide since the form in which it is com¬ 
bined is not known. Iron and aluminum are reported 
together as oxides since their separation is too time- 
consuming. The residue which separates on stand¬ 
ing should also be given. Results are preferably 
reported in percentages though some manufactur¬ 
ers are accustomed to grams per liter. The specific 
gravity and temperature should always be reported; 
for this reason also, a standard temperature should 
be used so that results would be really compara¬ 
ble. 

When the positive and negative ions are calculated 
to compounds they should nearly satisfy each other. 
It should be borne in mind, however, that the iron, 
aluminum and silicon are given as oxides, and not as 
salts, in which form they usually occur in the brine. 

1 “Monographien u. angewandte Electrochemie. fiber d. elektrolytische 
Gewinnung von Brom,” by Max Schlotter. 


There may also be small amounts of C 0 2 and iodine 
which are not included. If, however, the check is 
not reasonably close, it indicates an error, or else 
some undetermined constituent is present. 

As an illustration of the extremes in composition 
which the analyst must expect to meet, two examples 
from Ohio brines will serve. 


Brine Source: Eastern Ohio Coal Mine 

Specific gravity. 1.034 

Baume equivalent. 4.8° 

Sodium chloride. 3.26 per cent 

Magnesium bromide... 0.007 

Bromine. 0.006 

Calcium chloride. 1.63 

Magnesium chloride. 0.05 

Calcium sulfate. 0.001 

Iron and aluminum oxides.... 0.21 

Silica. 0.12 

Residue on evaporation. 5.23 


Southern Ohio Driven Well 

1.180 

22 . 2 ° 

12.08 per cent 
0.124 
0. 107 
10.81 
2.61 
0.03 
0.04 
0.002 
29.00 


While this work considers primarily the commercial 
natural brines, the same procedure will doubtless ap¬ 
ply to the analysis of artificial brines, such as used in 
soda ash manufacture and in electrolytic cells, although 
the amounts of calcium and magnesium will be much 
less in these solutions. 

Laboratory of Industrial Chemistry 
OhioIState University. Columbus 


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